Regulation of S. aureus Colonization by NO.

NO 对金黄色葡萄球菌定殖的调节。

• 批准号: 9075111
• 负责人: Ferric C Fang
• 金额: $ 36.41万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9075111
• 关键词: Bacterial Physiology; Biochemical; Biological Assay; Cell Respiration; Cells; Disease; Electron Transport; Environment; Enzymes; Gene Expression; Genes; Genetic; Human; Immune; Individual; Infection; Mediator of activation protein; Metabolism; Metals; Minority; Modeling; Molecular; Mus; Nitrate Reductases; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nose; Oxidation-Reduction; Oxygen; Physiology; Play; Prevention; Proteins; Regulation; Research Project Grants; Respiration; Role; Signaling Molecule; Staphylococcus aureus; Sulfhydryl Compounds; Testing; Virulence; in vivo; microorganism growth; mouse model; novel; novel strategies; pathogen; public health relevance

 DESCRIPTION (provided by applicant): Approximately two billion people are colonized with Staphylococcus aureus worldwide, but only a minority of these individuals will develop invasive infections. This application focuses on the role of nitric oxide (NO*), a molecular mediator that modulates bacterial physiology by targeting protein thiols and metal centers, during nasal colonization by S. aureus. We will test the hypothesis that NO* inhibits virulence and regulates microaerobic respiration in S. aureus. Our preliminary observations suggest that NO* is a critical determinant of whether S. aureus exists in a stable commensal relationship with the host or becomes an invasive pathogen. Our specific aims are to: (1) Assess the mechanism of S. aureus virulence gene inhibition by NO* - We have found that NO* inhibits the expression of virulence genes required for invasive infection. Genetic and biochemical approaches will determine how exogenous NO* inhibits virulence gene expression, focusing on AgrA, MgrA, SarR and SarS, four central transcriptional regulators that are S- nitrosylated by NO*. A novel murine nasal colonization model will be used to determine the effects of host-derived NO* on S. aureus virulence gene expression in vivo. (2) Analyze the regulation of S. aureus microaerobic physiology and colonization by NO* - S. aureus produces its own NO* by expressing an enzyme (saNOS) related to mammalian NO* synthases. We have discovered that saNOS is required for redox sensing during the microaerobic transition from aerobic respiration to nitrate respiration and for nasal colonization in mice. This aim will use expression and biochemical assays to test a novel mechanistic model in which bacterial-derived NO* diverts electron transport to nitrate reductase when O2 concentrations are limiting. Our mouse model will be used to assess the contribution of host- and bacterial-derived NO* to S. aureus colonization in vivo. These studies will establish NO* as a critically important signaling molecule that allows S. aureus to adapt to oxygen-limited conditions within the host environment while maintaining it in a commensal state by modulating virulence gene expression.

 描述（由申请人提供）：全世界约有 20 亿人感染金黄色葡萄球菌，但其中只有少数人会发生侵袭性感染。本申请重点关注一氧化氮 (NO*)（一种调节细菌的分子介质）的作用。在金黄色葡萄球菌鼻定植过程中，我们将通过靶向蛋白质硫醇和金属中心来检验 NO* 抑制毒力并调节的假设。我们的初步观察表明，NO* 是金黄色葡萄球菌是否与宿主存在稳定的共生关系或成为侵入性病原体的关键决定因素。 NO* 对金黄色葡萄球菌毒力基因的抑制 - 我们发现 NO* 抑制侵入性感染所需的毒力基因的表达。遗传和生化方法将决定外源性 NO* 如何抑制。毒力基因表达，重点关注 AgrA、MgrA、SarR 和 SarS，这四种被 NO* 进行 S-亚硝基化的中央转录调节因子 将使用一种新型小鼠鼻定植模型来确定宿主来源的 NO* 对金黄色葡萄球菌的影响。 (2) 分析 NO* 对金黄色葡萄球菌微氧生理和定植的调节 - 金黄色葡萄球菌通过以下方式产生自己的 NO*。表达与哺乳动物 NO* 合酶相关的酶 (saNOS) 我们发现 saNOS 是从有氧呼吸到硝酸盐呼吸的微有氧转变过程中氧化还原传感所必需的，并且是小鼠鼻腔定植的必要条件。一种新颖的机制模型，其中当 O2 浓度受到限制时，细菌衍生的 NO* 将电子传递转移至硝酸盐还原酶。这些研究将确定 NO* 作为一种至关重要的信号分子，使金黄色葡萄球菌能够适应宿主环境中的缺氧条件，同时通过调节将其维持在共生状态。毒力基因表达。